1. Field of the Invention
This invention relates to an amplifier circuit for the unadulterated transmission of phase information of a supplied ac voltage signal over a large dynamic range.
2. Description of the Prior Art
The allowed German application No. 2,439,612 discloses a process for the amplitude measurement of pulses which have considerable differences in level and in which the pulses are fed to an attenuation element which can be set up electronically in stages, and thereafter to a rectifier, and where the pulses are fed to a control circuit, which, whenever a specific positive or negative threshold voltage of a pulse is overshot, sets the next higher attenuation stage of the attenuation element. The rectified pulses are fed to a maximum value detector which, on reaching a positive or negative pulse maximum for analysis pulses, on the one hand, switches through a signal level value derived from the setting of the attenuation element and, on the other hand, switches through the established maximum value for interpolation in the range between the set attenuation stage and the attenuation stage of the attenuation element which is no longer reached.
Assuming equivalence of attenuation element and amplifier, the aforementioned publication discloses a possibility of phase-accurate ac voltage amplification over a large dynamic range, in which a switching amplifier is used by which automatic, stepped reduction of its amplifiers is always set in such a manner that it is not overmodulated. However, here a distortion-free transmission of the phase information of ac voltage signals is possible only when the amplifier operates in the linear portion of its amplification curve.